One disadvantage of industrial development and urbanization is discharge of exhaust gas. The exhaust gas discharged usually comprises toxic gases such as sulphur oxides and nitrogen oxides (SOX and NOX), as well as carbon oxides such as carbon dioxide. The above discharged exhaust gas are acidic gases.
The above acidic gases are adsorbed by solid adsorption materials. Solid amine adsorption material, especially, has become a research focus. These solid adsorption materials that load amine functional groups per se are porous adsorption materials. Amine functional groups at the terminal of amine molecules can effectively capture acidic gases. Thus when said adsorption materials contact the gas needed to be adsorbed, the synergism of physical adsorption and chemical adsorption greatly improve the adsorption efficiency.
Among the existing technologies, the way in which amine and support are bound mainly includes impregnation and chemical bond grafting. The impregnation preparation process is simple, and high content amine is easily obtained, resulting in high absorbing ability. However, amine is not tightly bound to the support, which may suffer loss due to volatilization at higher temperatures. As to the absorbent prepared by chemical bond grafting, the amine group is linked to the support via chemical bonds, and the absorbent has a high stability. However, the preparation process of chemical bond grafting is complicated, the grafting amount of the amine group is relatively low, and the absorbing ability is poorer than that of the absorbent prepared by impregnation.
In terms of solid support selection, several researchers have conducted experiment on porous supports, such as silica, alumina, molecular sieve, activated carbon. In terms of organic amine selection, MEA, PEI, DEA, TEPA, and the like are mainly chosen.
In the course of preparing solid amine adsorption materials, organic amine with suitable molecular size shall be matched with pore diameter and specific surface of the suitable solid support, so that organic amine molecules can enter the inside of pore channels as far as possible to be evenly loaded on the surface of the solid support.
M. L. Gray employed the impregnation method to synthesize a solid amine adsorption material by utilizing fly ash as support to load CPAHCL, the maximum adsorbing ability thereof was 1 wt % only (CO2 capture by amine-enriched fly ash carbon sorbents, M. L. Gray, Y. Soong, K. J. Champagne, John Baltrus, R. W. Stevens, Jr, P. Toochinda, S. S. C. Chuang, Separation and Purification Technology 35 (2004) 31-36). Steven Chuang employed the impregnation method to synthesize a solid amine adsorption material by utilizing Beta-molecular sieve to load TEPA, and the maximum adsorbing ability thereof was 9.13 wt % (Oxide-Supported Tetraethylenepentamine for CO2 Capture, James C. Fisher II, Jak Tanthana, and Steven S. C. Chuang, Environmental Progress & Sustainable Energy (Vol. 28, No. 4)).
The solid adsorption materials introduced by the above documents did not have an ideal adsorption effect, the highest carbon dioxide adsorption rate thereof was about 10 wt %. It is possible that in actual situation, compared to the theoretical value, organic amine is not evenly distributed, amine functional groups at the terminal of amine molecules fail to form effective carbon dioxide capture sites on the solid surface and the inside of pore channels homogeneously; or the interaction between amine functional groups at dendrimers and active sites on the surface of the solid support impacts the effective capture of carbon dioxide molecules.
In order to solve the problems existing in the prior art, i.e. a complicated process for preparing a solid amine gas adsorption material, necessity of special equipment or high costs, and poor selectivity, stability and adsorption capacity of the existing solid amine gas adsorption material, the inventors provided a novel method for preparing a solid amine gas adsorption material as well as the solid amine gas adsorption material prepared by the method and use thereof.